In a wireless communication system, a sending end and a receiving end may generally adopt multiple antennas for sending and receiving so as to acquire a higher rate. One principle of multi-antenna technology is to form multi-layer transmission matching with channel characteristics by taking advantage of some characteristics of a channel, and a radiation direction of a signal is highly targeted, which may effectively improve performance of a system, and the performance is significantly improved without increasing bandwidth and power. The multi-antenna technology is a very promising technology and has been widely applied to existing systems. Data transmission performance of a multi-antenna system mainly depends on measurement and feedback of channel information. Therefore, the measurement and feedback of the channel information are core contents of the multi-antenna system, and it becomes an important problem on how to ensure accuracy of channel measurement and channel information feedback, overhead and robustness.
The measurement and feedback of CSI are designed simply in an early long term evolution (LTE) system. However, with increasing requirement of accuracy, a pilot overhead, a feedback overhead and quantification complexity are not expected to increase significantly. Therefore, a measurement and feedback technology of the CSI becomes more and more complicated so as to achieve higher quantification efficiency. In addition, a plenty of new designs are introduced because a good adaptability is required for a variety of scenarios and antenna configurations.
The inventors, during inventing the disclosure, find that the measurement and feedback of the CSI in the conventional art has at least following disadvantages.
A base station periodically sends a precoding pilot (beamformed channel state information reference signal, BFed CSI-RS) and each feedback is based on identical CSI-RS resource configuration. However, the sending of the CSI-RS and the feedback of the CSI cannot be changed flexibly according to a channel state.
In addition, the base station semi-statically configures a BFed CSI-RS through a radio resource control (RRC) signaling. The BFed CSI-RS does not be changed for a long time after the configuration, which accordingly lacks flexibility of adapting dynamic changes of the channel.